In the capable World War II historical thriller "Valkyrie," Tom Cruise plays a real-life German officer who helped hatch a 1944 conspiracy to assassinate Adolf Hitler that -- spoiler alert! -- ultimately failed.

And therein lies the challenge for Cruise and superhero director Bryan Singer ("X-Men," "Superman Returns"). How do you generate genuine suspense when everybody knows the ending?

In the hit-and-miss, but ultimately entertaining "Valkyrie," Singer does it with characteristic big-budget flair.

Although his film is marred by a muddled first half -- making it difficult to keep track of which Nazi is which and exactly how their heavily politicized plan is supposed to work -- "Valkyrie" is redeemed by a quickly paced and gripping second hour.

It's there that Singer and company leave all the political plotting behind and get on with the action.

Tom Cruise in Valkyrie.

VALKYRIE 2.5 stars, out of 4

Plot: A Nazi officer spearheads an attempt to assassinate Adolf Hitler in a story based on real events.

What works: Director Bryan Singer knows how to do action, and when his film quits talking and finally gets around to that, it's fairly gripping.

What doesn't: The first half of the film, as the plan is being hatched, is disappointingly muddled.

(And, not to sound like Grandpa Scott -- U.S. Army, Battle of the Bulge, 1945 -- but they also do it with unusual auditory vigor. At an advance screening last week at the AMC Palace 20 Elmwood in Harahan, the big bangs bordered on painful at times.)

"Valkyrie" tells the story of Nazi Col. Claus Von Stauffenberg (played by a firmly-within-his-comfort-zone Cruise), who was part of a sophisticated inside plan to kill Hitler. (The title of the film comes from an internal Nazi defensive blueprint -- Operation Valkyrie -- that the plotters aimed to exploit in executing their plan.)

As Singer makes clear, Von Stauffenberg and his confederates hatched their plan after realizing that the war was lost for Germany and that Hitler was a madman. "I am a soldier," Von Stauffenberg says. "I serve my country. But this is not my country."

Killing Hitler was only one part of a larger plan, however. The plotters also wanted to snatch power from Hitler's high command and negotiate a truce with the Allies, thus sparing their country a certain amount of indignity and leaving it with at least a shred of capital at the bargaining table.

Even with its real-life backstory, "Valkyrie" ends up often feeling more popcorny than it does historical. That just happens when you have one Nazi with an American accent, several Nazis with British accents and a few with actual German accents.

Still, with rich production values and Singer's sensibilities, it's a nicely handled story, with a Panzerful of built-in intrigue -- even if the good guys do lose.